Problem: What do the following two equations represent? $2x-y = -3$ $4x+8y = -5$
Putting the first equation in $y = mx + b$ form gives: $2x-y = -3$ $-y = -2x-3$ $y = 2x + 3$ Putting the second equation in $y = mx + b$ form gives: $4x+8y = -5$ $8y = -4x-5$ $y = -\dfrac{1}{2}x - \dfrac{5}{8}$ The slopes are negative inverses of each other, so the lines are perpendicular.